Electric fluid heater



Nov. 14, 1950 E. l.. GRUPP 2,529,688

ELECTRIC FLUID HEATER Filed April 26, 1947 2 Sheet's-Sheet l mmmmm lll.,

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INVENTOR.

Nov. 14, 195o E. L. @UPP 2,529,688

ELECTRIC FLUID HEATER Filed April 26, 1947 2 Sheets-Sheet 2 d N l 1 wwwPatented Nov. 14, 1950 UNITED STATES PATENT OFFICE ELECTRIC FLUID HEATER-Edward L. Grupp, Glendale, Calif.

Application April 26,1947, Serial N o. 744,145

This invention relates to an electric fluidheater, and more particularlybut not necessarily to an electric water heater.

All of the electrical water heaters known to me are objectionable inthat the electrical groundy loss is greater than that permitted by theunderwriters in some districts. Also they do not provide for heatingwater of diierent conductive characteristics. Particularly, heaterswhich use the water as resistance to conduct the current between theelectrodes and heat the water by subjecting it to the electrolyticaction of the current do not provide means for varyingthe effective areaof the Yelectrodes to compensate for the different mineral content ofwater to be heated.

It is therefore a primary object of this invention to provide anelectric water heater that will overcome the above diculties.

Another object is to provide an electricwater heater wherein the casingcontaining the heating elements and other parts is insulated in such amanner as to reduce the electrical ground loss from the unit to aminimum and thereby lrender the heater safe for usefin any locationwhere such a heater is desired.

Another `object is to provide in a heater having the abovecharacteristics novel electrodes adjustable for varying the distancebetween the electrodes and adjustable for varying the effective area ofthe. electrodes in order to obtain the proper lelectrolytic action onVwaters of different.

mineral contents.

-A further object is to provide a heater ofnovel construction andarrangement of parts that will be durable, eftlcient in operation andcomparatively cheap to manufacture.

A still further object is to provide a heater in which the heatingelement is energized in response to the supply of water to the Vheaterand deenergized when the supply of water to the heater is stopped.

'I'he above and other objects will'be made apparent throughout thefurther description of the invention when Vtaken in connection with theaccompanying drawings, wherein like reference characters refer to likeparts. It is to be distinctly understood that the drawings are not adenition of the invention but merely illustrate one form `by means ofwhich the invention may be eifectuated.

In the drawings:

Fig. 1 -is a front elevational view having the cover removed, partly insection, and with certain parts broken away in order to disclose detailsof the invention.

`8 Claims. A(Cl. 219-40) Fig. 2 is a sectionalview taken along the lineII-II 0f Fig. l.

Fig. 3 is a sectional view taken along the lineembodied in theinvention.

Referring to the-drawings, thefpresent heater may include a housing orcasing, represented in its entirety-by IQ. The housing provides aheating* unit compartment I-I, a switch compartment I2, and a cylinderI3.

side I1, and the walls I8 ofthe cylinder I3 may be cast, molded, orotherwise formed to providean integral structure. ing may consistof acover plate 2| for the heating unit compartment I-I and a cover plate 22for the Lswitch compartment I2. terminates at its outer end in aninwardly eX- tending flange 23, the latter forming .theother end ofthe-housingvlll.

One of the important featureSo'f the invention is the provision ofsuitable insulation of the housing in order to reduce the electricalground loss of the vheating unit to a minimum. I have found byexperiment that effective insulation for this purpose may be obtained byconstructingV the housing-of aluminum or brass and providing the housingwith a 4high dielectric coating of phenolic resinoid. A suitableinsulating compound for this purpose consisting of a phenolic resinoidis known to the ytrade as Heresite I Vhave also discovered that acoating of phenolic resinoid of one mil thickness When properly appliedto aluminum or brass is effective for properly insulating a voltage asvhigh as 18'00 volts. The

housing is sprayed both internallyand externally:

with phenolic resinoid to provide a coating of the desired thickness,after which time the coats' ing is baked. The baking may be at 220 F;for

a period of twenty-four hours, or at 500 F. for ten minutes. Phenolicresinoidcoating has high thermal shock resistance and is tasteless andodorless.

The compartments :IIY and i2 of the housing are separated by a verticaltransverse partition' 26. The partition 26 is integral with the back I4,top I5, and bottom I of the housing I0 and is provided with a phenoliccoating the same ias above described. The interior ofthe heating unitcompartment II is further lined .with an Vinsulation strip 25 ofphenolic material having avthickness of T36 of an inch. The heating unitconsists Inthe construction of the housing IIJ, the back I4, top I5,bottom I6, onef The front of the hous- The cover plate -22 of a pair ofplate-like carbon electrodes 21 and 28 spaced apart by spacer members3l, a pair of contact plates 32 and 33 adapted to lie flat against theopposing faces of electrodes 21 and 28, respectively, a pair of curvedor arcuate shaped spring members 35 and 36, and a split, ceramic casingcomposed of two parts 31 and 38. The arcuate shaped spring member 35 isdisposed between casing part 31 and contact plate 32, while springmember 36 is disposed between casing member 38 and contact plate 33. Itcan now be understood that when the ceramic casing parts 31 and 38 areurged toward one another by the cover 2|, the spring members 35 and 36will be compressed and urge their respective adjacent contact plates 32and 33 into contact withthe respective opposing faces of electrodes 21and 28, the electrodes 21 and 26 being held in spaced relation by spacermembers 3 I. The spacer members 3l are made of suitable insulatingmaterial and arepreferably roundgand present flat, annular faces on eachof their sides, one'of their sides being provided with a centrallydisposed lug or projection 42, adapted to engage corresponding openings43 provided ,in the'inner face of one of the electrodes. Spacer members3I of different thickness may be provided for adjusting the spacingbetween the electrodes and the required number of spacer members may beinserted between the electrodes to provide the desired effective area ofthe electrodes. By the use of spacer members of different thickness toadjust the spacing between the electrodes, and by increasing ordecreasing the eective area of the electrode by varying the number ofspacer members between the electrodes, the heater may be easily andquickly converted for proper heating of waters of diiferent mineralcontent.

The contact plate 32 is slit at 45 to form a terminal strip 46. Theterminal strip 46 terminates in an inwardly extending tab 41 having anopening therein for receiving one end of a terminal 48 and is xedthereto by any suitable means, such as the threaded means shown at 49.The terminal 48 extends through an opening 46 in the partition'26 and issuitably insulated therefrom by a porcelain cover 5I. `The terminal 43and cover 5I are preferably formed integral with each other andathreaded means 52 may also be formed integral with cover 5I in order tomake a fluid-tight unit. The opening 46 may be internally threaded andcounterbored to form an annular beveled shoulder to cooperate With thebeveled inner end of the threaded means 52 and a copper washer insertedtherebetween as shown at 54 to insure a water-tight connection.

The contact plate 33 is slit adjacent its top at 56 to form a terminalstrip 51. The terminal strip 51 terminates in an inwardly extending tab58 having an opening 59 therein for receiving one end of a terminal 6I.-The terminal 6I' is mounted through an opening in the partition 26,insulated therefrom, and forming a Watertight connection therewith inthe same manner as that described in connection with terminal 48. Inorder to provide space Within the heating unit compartment Ii for thetab 41, terminal 48 and their threaded connecting means 49, the part 31of the ceramic casing, spring member 35 and electrode 21 are recessed,as shown at 62,. Space is likewise provided within the compartment IIfor tab 58, terminal 6I and their associated threaded connecting means49 by recesses in ceramic casing part 38, spring member 36 and electrode28, as shown at 63.

of cylinderA i3..

The ends of terminals 48 and 6I within the switch compartment areelectrically connected to a source of current by conductors 64 and 65respectively. The conductors enter the switch compartment by Way of aconduit 66 extending into an opening 61 provided in the top I5 of thehousing I9. The end of the conduit may be rigidly fixed to the top I5 bymeans of the threaded connection 68. Interposed within the electricalcircuit, comprising the 'conductors 64 and 65, is a switch or circuitbreaker 69 having a switch arm 16 for actuating the switch in the `usualmanner.

It will be noted from Figs. 2 and 4 that the f present device diiTersfrom prior constructions in three principal characteristics. First, thespring members 35 and 36 contact plates 32 and 33 and electrodes 21 and28 are spring-held within the casings 31 and 33 in what may be termedfloating therewithin. This `permits expansion and contraction of thesprings 35 and 36 and contact plates 32 and 33 without exerting undue.stress on the electrodes ,21 and `28 and thereby prevents the usualVcracking and distorting of the latter. Second, the positioning of thecontact plates 32 and 33 between their respective springs and electrodesprotects electrodes 21 and 23 from friction due to relative movement ofthe Springs 35 and 36, thereby greatly lengthening the life of theelectrodes 21 and 28. Third, the particular` fabrication of the heatingunit Whereby spacer members of a selected area and thickness may beemployed in such numbers as may be required for varying the distancebetween the electrodes for varying the effective area of saidelectrodes. Moreover, the present heating unit may be readilydisassembled for inspection, replacement of any one element or repair,and quickly and readily reassembled into a compact, effective unit.

In the present invention it is desired to actuate the switch f orenergizing the heating unit in response to the water supplied to theheating unit and to deenergize the heating unit when the supply of wateris cut off from the heating unit. To this end, water is supplied to theunit by way of an inlet pipe 1I connected to the outer'end threadednipple 12, the latter Yhaving -an internally threaded bore13, forreceiving the threaded i The cylinder AI3 is connected end of pipe 1I.with the heating compartment I I by Way of a slot or elongatedpassageway 14 provided througl'ry the topof` the wall ofthe cylinder I3.For actuating the switch 69 to energize or deenergize the,

heating unit in response to demand for hot water from the heating unit,a piston'15 is provided within the cylinder bore i3. v The piston 15 isbiased by a spring 16 toward its outermost posi-v tion in the cylinder,at which position its outer,y

face rests against theinner face of nipple 12. The piston 15 ispreferably of the full-floating type and a spring-retaining cap 11l isiplaced; against the inner face of the piston 15 for engaging the outerend of coil spring16. 'IheotherI end of coil spring 16 engages the innerclosed end 18 of the cylinder I3; The closed end 18 ofv threaded end ofa switch-actuating rod 19, as shown at 80. The rod 19'y extends axiallythrough l the cylinder I3, packing gland 8I,provided in the Theouterend'of cylinder I3 is internally threadedffor receiving 'anexternallyv rearvend 18 of cylinder I3, into the switch compartment I2,and terminates in a guide 82 carried by a bracket 83 iixed to the backMvof the housing I by any suitable means,such asscrews 84. A portion ofrod 19 within theswitch compartment and immediately below the switch armis threaded to .receive two adjusting nuts 85 spaced apart. Between thenutssthere is positioned on the .shaft 19 a member 86 formed to providea pair of spaced, upstanding arms 81 and 88 between which the end ofswitch arm 10 extends.

It can now be understood that when water is supplied to the cylinder i3by way of intake pipe.

1I, the force of the water will urge the piston against the tension ofthe spring 16 inwardly suiliciently to permit the passage of water fromthe cylinder I3 through the passageway 1.4 into the heating unit. Sincepiston 15 is appreciably shorter than passageway 14, water pressures onopposite sides of the piston readily balance each other, and the pistonquickly responds to drop in pressure in chamber II when faucets in line89 are opened.

As the piston is moved inwardly, the rod 19 will also move accordinglyand cause the member 81 to move the switch arm 10 into close positionand energize the heating unit. The heated water passes out the top ofthe heater by way of outlet pipe 89 connected with the top of thehousing I 8, as shown at 90. Upon cutting oif the water supply to thecylinder I3, the spring 16 will urge the spring-retaining cap 11 andpiston 15 to their outermost positions and since the rod 19 is -xed tothe cap 11, the rod will be moved to the right and cause member 88. tomove the switch arm 18 to break the circuit and deenergize theheating'unit. It is to be understood in connection with the aboveexplanation, that a faucet or faucets may be located in line 89 andwater is continually present within the heater. When a faucet in line 89is opened, pressure within the heater (and within bore I3) isreduced,.causing line pressurein supply pipe 1I to move piston 15 andsupply a stream of water to the heater.

A tubular stop member 9I may be carried by the inner face of the glandmember 8| for limiting the inner travel of the spring cap and piston.Also a roller support or guide 92 may be provided in the switchcompartment for contact with the bottom of member 86 for assisting inthe support and guiding of the rod 19.

In order to equalize and compensate for the differential pressuresbetween the interior of the cylinder and the heating unit when 'piston15 reaches closed position, there is provided a bypass 93 adjacent theinner end of nipple 12. An adjusting screw 94 may be provided in thehousing and connect the by-pass 93 for adjusting the same. The rear endof the piston 15 maybe beveled or provided vwith recesses for connectingthe interior of the intake pipe 1I with the bypass 93 when the piston'I5 is in closed position.

In the bottom of the wall of the cylinder I3 there is provided a drainplug 95 for draining the heating unit and cylinder during cold weatherwhen the heater is not in use. Also there is provided a trap 96 in thebottom of the switch compartment for catching any leak-age from thegland 8l, the trap 99 being provided with a plug 91 for draining thetrap.

Accordingly there is provided an electric heater for water or otherfluids that is so constructed and insulated as to insure a minimumelectric ground loss, which can. befadjustedfor the proper.

inexpensive to operate and comparatively cheap.

to manufacture.

While only one form of the inventionhas been illustrated and described,itwill nowv be apparent. to those skilledinthe art. that certainchanges, additions, omissions, and substitutions may be made in theexemplary form shown Withoutdeparting from the spirit andscope of theinvention as deiined by the appended claims.

I claim: Y

1. A fluid heater including: a.housing;A a partition in said housingforming two compartments; a cylinder in said housing; an electricVswitch in one of said compartments; a heating unit in the other. of saidcompartments, said heating unit comprising a pair of electrodes;

means for biasing said electrodes toward one another; and means forretaining said electrodes at a desired distance apart, said biasingmeans being supported in floating relation to the rst named compartment;an electric conductor connecting said switch and said heating unit;means for connecting a source of current tosaid switch; a piston in saidcylinder; a fluid inlet and a fluid outlet connected with said heatingunit compartment; means actuated by said piston in response to uidpressurein said inlet for actuating said switch, and an adjustable.portv connecting said inlet with said other compartment for equalizingthe pressure therebetween.

2. An electrically energized instantaneous water heater including: anouter metallic housing; a compartment in said housing; an inlet bore inthe housing near one end of said compartment; a port connecting saidbore and compartment; an outlet port in the housing in communicationwith the other end of the compartment; a pair of opposing, dielectriccasings in the compartment; an electrode plate in each casing; springmeans between each casing and its electrode urging vsaid electrodestoward each other; andv removable spacer means between said electrodesand attached thereto, the said electrode plates and spring means beingsupported in iioating relation with said casings.

3. An electrically energized instantaneoustype water heater, comprising:an outer metallic relatively at housing provided with a transversepartition dividing said housing into a switch compartment and a heatingcompartment, a piston bore in the bottom of the housing, an inlet portinto the end of the piston bore, a lateral passageway from the pistonbore in communication with one side of the heating compartment, anoutlet port in the top of the housing opposing the lateral passageway, aspring-biased piston in the bore, said piston normally closing the inletport, and a pair of flat electrodes in spaced relation in the heatingcompartment and between said lateral passageway and outlet port; atleast one of said electrodes being provided with a series of recesses,and removable spacer means arranged to be held in said recesses of oneelectrode and contact the opposite electrode to limit the eiectivesurface area of said electrodes.

4. In a iluid heater the combination of: a housing including a back,top, bottom and sides and an open front; a removable closure for thefront of the housing to form a compartment therein; a iluid inlet intothe bottom of the liousing and a uid outlet in the top of the housingaaaess 1. andin communication with the compartment; a ceramic casingWithin the compartment; a pair of imperforate electrodes in said casing;spring means biasing the electrodes towards each other and means formaintaining the electrodes in a predetermined, spaced, relationcomprising a plurality of spacer members carried by one of saidelectrodes, said spacer members being removable to Vary the eiectvesurface "area of the electrodes. Y

5. In a fluid heater the combination of: a housing provided with atransverse partition forming two compartments in said housing; a switchmeans positioned in one of said compartments; a cylinder formed in thewall of the housing below the second compartment; a fluid inlet into oneend of the cylinder; a port communicating the side of the cylinder withthe second compartment; a piston in the cylinder, said piston beingspring biased to normally close the fluid inlet; an adjustable pressureequalizing passageway between the second compartment and said cylinder,normally closed by said piston, said passageway communicating with thecylinder between the fluid inlet and port; a heating unit in the secondcompartment and connected to the switch means and means actuated by thepiston in response to fluid pressure in the inlet for actuating theswitch.

6. A fluid heater of the character stated in claim 5 wherein the heatingunit comprises a pair of imperforate electrodes, spring means biasingthe electrodes towards each other; and means for maintaining theelectrodes in predetermined, spaced relation comprising a plurality ofspacer members carried by one of said electrodes and in contact with theother electrode.

7. An electrically energized, instantaneous, water heater comprising: anouter metallic housing Vprovided with a partition dividing said housinginto two compartments; a switch in one of said compartments; an inletbore in the housing near one end of the second compartment; a portconnecting said bore and compartment; an

outlet port in the housing in communication with the other end of saidcompartment; a pair of opposing dielectric casings in the compartment;an electrode plate in each casing, said electrode plates being inparallel, opposing relation; spring means between each casing and itselectrode urging said electrodes towards each other; and removablespacer means between said electrodes and attached thereto, the saidelectrodes and spring means being supported in.

floating relation with respect to said casings; and piston means inoperative relation to said port arranged to actuate the switch inresponse to uid pressure in the inlet bore.

8. In an electrically energized, fluid heater the provision of: a pairof flat, imperforate electrodes in parallel relation and selective meansfor variably spacing said electrodes at a predetermined distance, saidmeans including a series of recesses in one of the opposing faces ofsaid electrodes and spacer members extending thereinto and contactingthe opposing electrode face, said spacer members being removable to varythe effective surface area of the electrodes.

EDWARD L. GRUPP.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 754,451 Hill Mar. 15, 19041,689,521 Dominguez Oct. 30, 1928 1,916,064 Mortensen June 27, 19331,941,584 Sexton Jan. 2, 1994 1,990,790 Lenz Feb. 12, 1935 2,257,841Elam Oct. 7, 1941 2,306,921 wncox Dec. 29, 1942 2,312,677 Shrum Mar. 2,1943 2,325,722 Walther Aug. 3, 1943 2,428,445 Wicks Oct. 7, 19472,429,112 Warren Oct. 14, 1947

